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EF架构~基于EF数据层的实现

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之前写过关于实现一个完整的EF架构的文章,文章的阅读量也是满大的,自己很欣慰,但是,那篇文章是我2011年写的,所以,技术有些不成熟,所以今天把我的2014年写的EF底层架构公开一下,这个架构比2011年的有了很大程度的提高,主要在接口规范,查询规范上,并引入了排序功能,两步对完善了EF对数据的批量操作,可以说,这次的架构是很有看点的。

一 一个基础操作接口

    /// <summary>    /// 基础的数据操作规范    /// 与ORM架构无关    /// </summary>    /// <typeparam name="TEntity"></typeparam>    public interface IRepository<TEntity>           where TEntity : class    {        /// <summary>        /// 设定数据上下文,它一般由构架方法注入        /// </summary>        /// <param name="unitOfWork"></param>        void SetDbContext(IUnitOfWork unitOfWork);        /// <summary>        /// 添加实体并提交到数据服务器        /// </summary>        /// <param name="item">Item to add to repository</param>        void Insert(TEntity item);        /// <summary>        /// 移除实体并提交到数据服务器        /// 如果表存在约束,需要先删除子表信息        /// </summary>        /// <param name="item">Item to delete</param>        void Delete(TEntity item);        /// <summary>        /// 修改实体并提交到数据服务器        /// </summary>        /// <param name="item"></param>        void Update(TEntity item);        /// <summary>        /// 得到指定的实体集合(延时结果集)        /// Get all elements of type {T} in repository        /// </summary>        /// <returns>List of selected elements</returns>        IQueryable<TEntity> GetModel();        /// <summary>        /// 根据主键得到实体        /// </summary>        /// <param name="id"></param>        /// <returns></returns>        TEntity Find(params object[] id);    }
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二 一个扩展操作接口

    /// <summary>    /// 扩展的Repository操作规范    /// </summary>    public interface IExtensionRepository<TEntity> :        IRepository<TEntity>,        IOrderableRepository<TEntity>        where TEntity : class    {        /// <summary>        /// 添加集合[集合数目不大时用此方法,超大集合使用BulkInsert]        /// </summary>        /// <param name="item"></param>        void Insert(IEnumerable<TEntity> item);        /// <summary>        /// 修改集合[集合数目不大时用此方法,超大集合使用BulkUpdate]        /// </summary>        /// <param name="item"></param>        void Update(IEnumerable<TEntity> item);        /// <summary>        /// 删除集合[集合数目不大时用此方法,超大集合使用批量删除]        /// </summary>        /// <param name="item"></param>        void Delete(IEnumerable<TEntity> item);        /// <summary>        /// 扩展更新方法,只对EF支持        /// 注意本方法不能和GetModel()一起使用,它的表主键可以通过post或get方式获取        /// </summary>        /// <param name="entity"></param>        void Update<T>(Expression<Action<T>> entity) where T : class;        /// <summary>        /// 根据指定lambda表达式,得到延时结果集        /// </summary>        /// <param name="predicate"></param>        /// <returns></returns>        IQueryable<TEntity> GetModel(Expression<Func<TEntity, bool>> predicate);        /// <summary>        /// 根据指定lambda表达式,得到第一个实体        /// </summary>        /// <param name="predicate"></param>        /// <returns></returns>        TEntity Find(Expression<Func<TEntity, bool>> predicate);        /// <summary>        /// 批量添加,添加之前可以去除自增属性,默认不去除        /// </summary>        /// <param name="item"></param>        /// <param name="isRemoveIdentity"></param>        void BulkInsert(IEnumerable<TEntity> item, bool isRemoveIdentity);        /// <summary>        /// 批量添加        /// </summary>        /// <param name="item"></param>        void BulkInsert(IEnumerable<TEntity> item);        /// <summary>        /// 批量更新        /// </summary>        /// <param name="item"></param>        void BulkUpdate(IEnumerable<TEntity> item, params string[] fieldParams);        /// <summary>        /// 批量删除        /// </summary>        /// <param name="item"></param>        void BulkDelete(IEnumerable<TEntity> item);    }
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三 一个排序操作接口

    /// <summary>    /// 提供排序功能的规范    /// </summary>    public interface IOrderableRepository<TEntity> where TEntity : class    {        /// <summary>        /// 带排序的结果集        /// </summary>        /// <param name="orderBy"></param>        /// <returns></returns>        IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy);        /// <summary>        /// 根据指定lambda表达式和排序方式,得到延时结果集        /// </summary>        /// <param name="predicate"></param>        /// <returns></returns>        IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy, Expression<Func<TEntity, bool>> predicate);    }
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四 基于ef架构的规约查询接口

/// <summary>    /// EF底层构架,关于规约功能的仓储接口    /// </summary>    /// <typeparam name="TEntity"></typeparam>    public interface ISpecificationRepository<TEntity> :        IExtensionRepository<TEntity>        where TEntity : class    {        /// <summary>        /// 根据指定规约,得到延时结果集        /// </summary>        /// <param name="specification"></param>        /// <returns></returns>        IQueryable<TEntity> GetModel(ISpecification<TEntity> specification);        /// <summary>        /// 根据指定规约,得到第一个实体        /// </summary>        /// <param name="specification"></param>        /// <returns></returns>        TEntity Find(ISpecification<TEntity> specification);        /// <summary>        /// 带排序功能的,根据指定规约,得到结果集        /// </summary>        /// <param name="orderBy"></param>        /// <param name="specification"></param>        /// <returns></returns>        IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy, EntityFrameworks.Entity.Core.Specification.ISpecification<TEntity> specification);        /// <summary>        /// 保存之后触发        /// Occurs after data saved        /// </summary>        event Action<SavedEventArgs> AfterSaved;        /// <summary>        /// 保存之前触发        /// Occurs before data saved        /// </summary>        event Action<SavedEventArgs> BeforeSaved;    }
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五 基于工作单元的标识接口

/// <summary>    /// 数据上下文标识接口,它对于业务层应该是公开的    /// 它对于实现上下文的方法,它并不关心,可以是linq2sql,ef,ado.net,nhibernate,memory,nosql等    /// </summary>    public interface IUnitOfWork    {    }
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六 基于ef的DbContext上下文的仓储的实现

 /// <summary>    /// DbContext上下文仓储功能类,领域上下文可以直接继承它    /// 生命周期:数据上下文的生命周期为一个HTTP请求的结束    /// 相关说明:    /// 1 领域对象使用声明IRepository和IExtensionRepository接口得到不同的操作规范    /// 2 可以直接为上下注入Action<string>的委托实例,用来记录savechanges产生的异常    /// 3 可以订阅BeforeSaved和AfterSaved两个事件,用来在方法提交前与提交后实现代码注入    /// 4 所有领域db上下文都要继承iUnitWork接口,用来实现工作单元,这对于提升程序性能与为重要    /// </summary>    /// <typeparam name="TEntity"></typeparam>    public class DbContextRepository<TEntity> :         ISpecificationRepository<TEntity>         where TEntity : class    {        #region Constructors        public DbContextRepository(IUnitOfWork db, Action<string> logger)        {            UnitWork = db;            Db = (DbContext)db;            Logger = logger;            ((IObjectContextAdapter)Db).ObjectContext.CommandTimeout = 0;        }        public DbContextRepository(IUnitOfWork db)            : this(db, null)        { }        #endregion        #region Properties        /// <summary>        /// 数据上下文        /// </summary>        protected DbContext Db { get; private set; }        /// <summary>        /// 工作单元上下文,子类可以直接使用它        /// </summary>        protected IUnitOfWork UnitWork { get; set; }        /// <summary>        /// Action委托事例,在派生类可以操作它        /// </summary>        protected Action<string> Logger { get; private set; }        #endregion        #region Fields        /// <summary>        /// 数据总数        /// </summary>        int _dataTotalCount = 0;        /// <summary>        /// 数据总页数        /// </summary>        int _dataTotalPages = 0;        /// <summary>        /// 数据页面大小(每次向数据库提交的记录数)        /// </summary>        private const int DataPageSize = 10000;        #endregion        #region Delegates & Event        /// <summary>        /// 保存之后        /// </summary>        public event Action<SavedEventArgs> AfterSaved;        /// <summary>        /// 保存之前        /// </summary>        public event Action<SavedEventArgs> BeforeSaved;        #endregion        #region IRepository<TEntity> 成员        public void SetDbContext(IUnitOfWork unitOfWork)        {            this.Db = (DbContext)unitOfWork;            this.UnitWork = unitOfWork;        }        public virtual void Insert(TEntity item)        {            OnBeforeSaved(new SavedEventArgs(item, SaveAction.Insert));            Db.Entry<TEntity>(item);            Db.Set<TEntity>().Add(item);            this.SaveChanges();            OnAfterSaved(new SavedEventArgs(item, SaveAction.Insert));        }        public virtual void Delete(TEntity item)        {            OnBeforeSaved(new SavedEventArgs(item, SaveAction.Delete));            Db.Set<TEntity>().Attach(item);            Db.Set<TEntity>().Remove(item);            this.SaveChanges();            OnAfterSaved(new SavedEventArgs(item, SaveAction.Delete));        }        public virtual void Update(TEntity item)        {            OnBeforeSaved(new SavedEventArgs(item, SaveAction.Update));            Db.Set<TEntity>().Attach(item);            Db.Entry(item).State = EntityState.Modified;            try            {                this.SaveChanges();            }            catch (System.Data.OptimisticConcurrencyException ex)//并发冲突异常            {                ((IObjectContextAdapter)Db).ObjectContext.Refresh(RefreshMode.ClientWins, item);                this.SaveChanges();            }            OnAfterSaved(new SavedEventArgs(item, SaveAction.Update));        }        /// <summary>        /// 子类在实现时,可以重写,加一些状态过滤        /// </summary>        /// <returns></returns>        public virtual IQueryable<TEntity> GetModel()        {            //  return Db.Set<TEntity>().AsNoTracking();//对象无法自动添加到上下文中,因为它是使用 NoTracking 合并选项检索的。请在定义此关系之前,将该实体显式附加到 ObjectContext。            return Db.Set<TEntity>();////ObjectStateManager 中已存在具有同一键的对象。ObjectStateManager 无法跟踪具有相同键的多个对象。        }        /// <summary>        /// 得到原生态结果集        /// </summary>        /// <returns></returns>        public IQueryable<TEntity> GetEntities()        {            return Db.Set<TEntity>();        }        #endregion        #region IExtensionRepository<TEntity> 成员        public virtual void Insert(IEnumerable<TEntity> item)        {            item.ToList().ForEach(i =>            {                Db.Entry<TEntity>(i);                Db.Set<TEntity>().Add(i);            });            this.SaveChanges();        }        public virtual void Delete(IEnumerable<TEntity> item)        {            item.ToList().ForEach(i =>            {                Db.Set<TEntity>().Attach(i);                Db.Set<TEntity>().Remove(i);            });            this.SaveChanges();        }        public virtual void Update(IEnumerable<TEntity> item)        {            item.ToList().ForEach(i =>            {                Db.Set<TEntity>().Attach(i);                Db.Entry(i).State = EntityState.Modified;            });            try            {                this.SaveChanges();            }            catch (System.Data.OptimisticConcurrencyException ex)//并发冲突异常            {                ((IObjectContextAdapter)Db).ObjectContext.Refresh(RefreshMode.ClientWins, item);                this.SaveChanges();            }        }        public void Update<T>(Expression<Action<T>> entity) where T : class        {            T newEntity = typeof(T).GetConstructor(Type.EmptyTypes).Invoke(null) as T;//建立指定类型的实例            List<string> propertyNameList = new List<string>();            MemberInitExpression param = entity.Body as MemberInitExpression;            foreach (var item in param.Bindings)            {                string propertyName = item.Member.Name;                object propertyValue;                var memberAssignment = item as MemberAssignment;                if (memberAssignment.Expression.NodeType == ExpressionType.Constant)                {                    propertyValue = (memberAssignment.Expression as ConstantExpression).Value;                }                else                {                    propertyValue = Expression.Lambda(memberAssignment.Expression, null).Compile().DynamicInvoke();                }                typeof(T).GetProperty(propertyName).SetValue(newEntity, propertyValue, null);                propertyNameList.Add(propertyName);            }            try            {                Db.Set<T>().Attach(newEntity);            }            catch (Exception)            {                throw new Exception("本方法不能和GetModel()一起使用,请使用Update(TEntity entity)方法");            }            Db.Configuration.ValidateOnSaveEnabled = false;            var ObjectStateEntry = ((IObjectContextAdapter)Db).ObjectContext.ObjectStateManager.GetObjectStateEntry(newEntity);            propertyNameList.ForEach(x => ObjectStateEntry.SetModifiedProperty(x.Trim()));            try            {                this.SaveChanges();            }            catch (System.Data.OptimisticConcurrencyException ex)//并发冲突异常            {                ((IObjectContextAdapter)Db).ObjectContext.Refresh(RefreshMode.ClientWins, newEntity);                this.SaveChanges();            }        }        public TEntity Find(params object[] id)        {            return Db.Set<TEntity>().Find(id);        }        public IQueryable<TEntity> GetModel(Expression<Func<TEntity, bool>> predicate)        {            return GetModel().Where(predicate);        }        public TEntity Find(Expression<Func<TEntity, bool>> predicate)        {            return GetModel(predicate).FirstOrDefault();        }        public void BulkInsert(IEnumerable<TEntity> item)        {            BulkInsert(item, false);        }        public void BulkInsert(IEnumerable<TEntity> item, bool isRemoveIdentity)        {            string startTag = "", endTag = "";            if (isRemoveIdentity)            {                startTag = "SET IDENTITY_INSERT " + typeof(TEntity).Name + " ON;";                endTag = "SET IDENTITY_INSERT " + typeof(TEntity).Name + "  OFF;";            }            DataPageProcess(item, (currentItems) =>            {                ((IObjectContextAdapter)Db).ObjectContext.CommandTimeout = 0;//永不超时                Db.Database.ExecuteSqlCommand(startTag                    + DoSql(currentItems, SqlType.Insert)                    + endTag);            });        }        public void BulkDelete(IEnumerable<TEntity> item)        {            DataPageProcess(item, (currentItems) =>            {                ((IObjectContextAdapter)Db).ObjectContext.CommandTimeout = 0;//永不超时                Db.Database.ExecuteSqlCommand(DoSql(currentItems, SqlType.Delete));            });        }        public void BulkUpdate(IEnumerable<TEntity> item, params string[] fieldParams)        {            DataPageProcess(item, (currentItems) =>            {                ((IObjectContextAdapter)Db).ObjectContext.CommandTimeout = 0;//永不超时                Db.Database.ExecuteSqlCommand(DoSql(currentItems, SqlType.Update, fieldParams));            });        }        #endregion        #region ISpecificationRepository<TEntity> 成员        public TEntity Find(ISpecification<TEntity> specification)        {            return GetModel(specification).FirstOrDefault();        }        public IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy, ISpecification<TEntity> specification)        {            var linq = new Orderable<TEntity>(GetModel(specification));            orderBy(linq);            return linq.Queryable;        }        public IQueryable<TEntity> GetModel(ISpecification<TEntity> specification)        {            return GetModel().Where(specification.SatisfiedBy());        }        #endregion        #region IOrderableRepository<TEntity>成员        public IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy)        {            var linq = new Orderable<TEntity>(GetModel());            orderBy(linq);            return linq.Queryable;        }        public IQueryable<TEntity> GetModel(Action<IOrderable<TEntity>> orderBy, Expression<Func<TEntity, bool>> predicate)        {            var linq = new Orderable<TEntity>(GetModel(predicate));            orderBy(linq);            return linq.Queryable;        }        #endregion        #region Protected Methods        /// <summary>        /// 根据工作单元的IsNotSubmit的属性,去判断是否提交到数据库        /// 一般地,在多个repository类型进行组合时,这个IsNotSubmit都会设为true,即不马上提交,        /// 而对于单个repository操作来说,它的值不需要设置,使用默认的false,将直接提交到数据库,这也保证了操作的原子性。        /// </summary>        protected void SaveChanges()        {            try            {                Db.SaveChanges();            }            catch (System.Data.Entity.Validation.DbEntityValidationException dbEx)//捕获实体验证异常            {                var sb = new StringBuilder();                dbEx.EntityValidationErrors.First().ValidationErrors.ToList().ForEach(i =>                {                    sb.AppendFormat("属性为:{0},信息为:{1}\n\r", i.PropertyName, i.ErrorMessage);                });                if (Logger == null)                    throw new Exception(sb.ToString());                Logger(sb.ToString() + "处理时间:" + DateTime.Now);            }            catch (System.Data.OptimisticConcurrencyException ex)//并发冲突异常            {                //保持数据源中对象的现有属性                //Db.Refresh(RefreshMode.StoreWins, person);                //  Db.SaveChanges();            }            catch (Exception ex)//捕获所有异常            {                if (Logger == null)//如果没有定义日志功能,就把异常抛出来吧                    throw new Exception(ex.Message);                Logger(ex.Message + "处理时间:" + DateTime.Now);            }        }        /// <summary>        ///  计数更新,与SaveChange()是两个SQL链接,走分布式事务        ///  子类可以根据自己的逻辑,去复写        ///  tableName:表名        ///  param:索引0为主键名,1表主键值,2为要计数的字段,3为增量        /// </summary>        /// <param name="tableName">表名</param>        /// <param name="param">参数列表,索引0为主键名,1表主键值,2为要计数的字段,3为增量</param>        protected virtual void UpdateForCount(string tableName, params object[] param)        {            string sql = "update [" + tableName + "] set [{2}]=ISNULL([{2}],0)+{3} where [{0}]={1}";            var listParasm = new List<object>            {                param[0],                param[1],                param[2],                param[3],            };            Db.Database.ExecuteSqlCommand(string.Format(sql, listParasm.ToArray()));        }        #endregion        #region Virtual Methods        /// <summary>        ///  Called after data saved        /// </summary>        /// <param name="e"></param>        protected virtual void OnAfterSaved(SavedEventArgs e)        {            if (AfterSaved != null)            {                AfterSaved(e);            }        }        /// <summary>        /// Called before saved        /// </summary>        /// <param name="e"></param>        protected virtual void OnBeforeSaved(SavedEventArgs e)        {            if (BeforeSaved != null)            {                BeforeSaved(e);            }        }        #endregion        #region Private Methods        /// <summary>        /// 分页进行数据提交的逻辑        /// </summary>        /// <param name="item">原列表</param>        /// <param name="method">处理方法</param>        /// <param name="currentItem">要进行处理的新列表</param>        private void DataPageProcess(IEnumerable<TEntity> item, Action<IEnumerable<TEntity>> method)        {            if (item != null && item.Any())            {                _dataTotalCount = item.Count();                this._dataTotalPages = item.Count() / DataPageSize;                if (_dataTotalCount % DataPageSize > 0)                    _dataTotalPages += 1;                for (int pageIndex = 1; pageIndex <= _dataTotalPages; pageIndex++)                {                    var currentItems = item.Skip((pageIndex - 1) * DataPageSize).Take(DataPageSize).ToList();                    method(currentItems);                }            }        }        private static string GetEqualStatment(string fieldName, int paramId, Type pkType)        {            if (pkType.IsValueType)                return string.Format("{0} = {1}", fieldName, GetParamTag(paramId));            return string.Format("{0} = ‘{1}‘", fieldName, GetParamTag(paramId));        }        private static string GetParamTag(int paramId)        {            return "{" + paramId + "}";        }        /// <summary>        /// 得到实体键EntityKey        /// </summary>        /// <typeparam name="TEntity"></typeparam>        /// <returns></returns>        protected ReadOnlyMetadataCollection<EdmMember> GetPrimaryKey()        {            EntitySetBase primaryKey = ((IObjectContextAdapter)Db).ObjectContext.GetEntitySet(typeof(TEntity));            if (primaryKey == null)                return null;            ReadOnlyMetadataCollection<EdmMember> arr = primaryKey.ElementType.KeyMembers;            return arr;        }        /// <summary>        /// 构建Update语句串        /// 注意:如果本方法过滤了int,decimal类型更新为0的列,如果希望更新它们需要指定FieldParams参数        /// </summary>        /// <param name="entity">实体列表</param>        /// <param name="fieldParams">要更新的字段</param>        /// <returns></returns>        private Tuple<string, object[]> CreateUpdateSql(TEntity entity, params string[] fieldParams)        {            if (entity == null)                throw new ArgumentException("The database entity can not be null.");            var pkList = GetPrimaryKey().Select(i => i.Name).ToList();            var entityType = entity.GetType();            var tableFields = new List<PropertyInfo>();            if (fieldParams != null && fieldParams.Count() > 0)            {                tableFields = entityType.GetProperties().Where(i => fieldParams.Contains(i.Name, new StringComparisonIgnoreCase())).ToList();            }            else            {                tableFields = entityType.GetProperties().Where(i =>                              !pkList.Contains(i.Name)                              && i.GetValue(entity, null) != null                              && !i.PropertyType.IsEnum                              && !(i.PropertyType == typeof(ValueType) && Convert.ToInt64(i.GetValue(entity, null)) == 0)                              && !(i.PropertyType == typeof(DateTime) && Convert.ToDateTime(i.GetValue(entity, null)) == DateTime.MinValue)                              && i.PropertyType != typeof(EntityState)                              && i.GetCustomAttributes(false).Where(j => j.GetType() == typeof(NavigationAttribute)) != null//过滤导航属性                              && (i.PropertyType.IsValueType || i.PropertyType == typeof(string))                              ).ToList();            }            //过滤主键,航行属性,状态属性等            if (pkList == null || pkList.Count == 0)                throw new ArgumentException("The Table entity have not a primary key.");            var arguments = new List<object>();            var builder = new StringBuilder();            foreach (var change in tableFields)            {                if (pkList.Contains(change.Name))                    continue;                if (arguments.Count != 0)                    builder.Append(", ");                builder.Append(change.Name + " = {" + arguments.Count + "}");                if (change.PropertyType == typeof(string)                    || change.PropertyType == typeof(DateTime)                    || change.PropertyType == typeof(DateTime?)                    || change.PropertyType == typeof(bool?)                    || change.PropertyType == typeof(bool))                    arguments.Add("" + change.GetValue(entity, null).ToString().Replace("", "char(39)") + "");                else                    arguments.Add(change.GetValue(entity, null));            }            if (builder.Length == 0)                throw new Exception("没有任何属性进行更新");            builder.Insert(0, " UPDATE " + string.Format("[{0}]", entityType.Name) + " SET ");            builder.Append(" WHERE ");            bool firstPrimaryKey = true;            foreach (var primaryField in pkList)            {                if (firstPrimaryKey)                    firstPrimaryKey = false;                else                    builder.Append(" AND ");                object val = entityType.GetProperty(primaryField).GetValue(entity, null);                Type pkType = entityType.GetProperty(primaryField).GetType();                builder.Append(GetEqualStatment(primaryField, arguments.Count, pkType));                arguments.Add(val);            }            return new Tuple<string, object[]>(builder.ToString(), arguments.ToArray());        }        /// <summary>        /// 构建Delete语句串        /// </summary>        /// <typeparam name="TEntity"></typeparam>        /// <param name="entity"></param>        /// <returns></returns>        private Tuple<string, object[]> CreateDeleteSql(TEntity entity)        {            if (entity == null)                throw new ArgumentException("The database entity can not be null.");            Type entityType = entity.GetType();            List<string> pkList = GetPrimaryKey().Select(i => i.Name).ToList();            if (pkList == null || pkList.Count == 0)                throw new ArgumentException("The Table entity have not a primary key.");            var arguments = new List<object>();            var builder = new StringBuilder();            builder.Append(" Delete from " + string.Format("[{0}]", entityType.Name));            builder.Append(" WHERE ");            bool firstPrimaryKey = true;            foreach (var primaryField in pkList)            {                if (firstPrimaryKey)                    firstPrimaryKey = false;                else                    builder.Append(" AND ");                Type pkType = entityType.GetProperty(primaryField).GetType();                object val = entityType.GetProperty(primaryField).GetValue(entity, null);                builder.Append(GetEqualStatment(primaryField, arguments.Count, pkType));                arguments.Add(val);            }            return new Tuple<string, object[]>(builder.ToString(), arguments.ToArray());        }        /// <summary>        /// 构建Insert语句串        /// 主键为自增时,如果主键值为0,我们将主键插入到SQL串中        /// </summary>        /// <typeparam name="TEntity"></typeparam>        /// <param name="entity"></param>        /// <returns></returns>        private Tuple<string, object[]> CreateInsertSql(TEntity entity)        {            if (entity == null)                throw new ArgumentException("The database entity can not be null.");            Type entityType = entity.GetType();            var table = entityType.GetProperties().Where(i => i.PropertyType != typeof(EntityKey)                 && i.PropertyType != typeof(EntityState)                 && i.Name != "IsValid"                 && i.GetValue(entity, null) != null                 && !i.PropertyType.IsEnum                 && i.GetCustomAttributes(false).Where(j => j.GetType() == typeof(NavigationAttribute)) != null                 && (i.PropertyType.IsValueType || i.PropertyType == typeof(string))).ToArray();//过滤主键,航行属性,状态属性等            var pkList = new List<string>();            if (GetPrimaryKey() != null)//有时主键可能没有设计,这对于添加操作是可以的                pkList = GetPrimaryKey().Select(i => i.Name).ToList();            var arguments = new List<object>();            var fieldbuilder = new StringBuilder();            var valuebuilder = new StringBuilder();            fieldbuilder.Append(" INSERT INTO " + string.Format("[{0}]", entityType.Name) + " (");            foreach (var member in table)            {                if (pkList.Contains(member.Name) && Convert.ToString(member.GetValue(entity, null)) == "0")                    continue;                object value = http://www.mamicode.com/member.GetValue(entity, null);                if (value != null)                {                    if (arguments.Count != 0)                    {                        fieldbuilder.Append(", ");                        valuebuilder.Append(", ");                    }                    fieldbuilder.Append(member.Name);                    if (member.PropertyType == typeof(string)                        || member.PropertyType == typeof(DateTime)                        || member.PropertyType == typeof(DateTime?)                        || member.PropertyType == typeof(Boolean?)                        || member.PropertyType == typeof(Boolean)                        )                        valuebuilder.Append("‘{" + arguments.Count + "}‘");                    else                        valuebuilder.Append("{" + arguments.Count + "}");                    if (value is string)                        value = value.ToString().Replace("", "char(39)");                    arguments.Add(value);                }            }            fieldbuilder.Append(") Values (");            fieldbuilder.Append(valuebuilder.ToString());            fieldbuilder.Append(");");            return new Tuple<string, object[]>(fieldbuilder.ToString(), arguments.ToArray());        }        /// <summary>        /// /// <summary>        /// 执行SQL,根据SQL操作的类型        /// </summary>        /// <typeparam name="TEntity"></typeparam>        /// <param name="list"></param>        /// <param name="sqlType"></param>        /// <returns></returns>        /// </summary>        /// <param name="list"></param>        /// <param name="sqlType"></param>        /// <returns></returns>        private string DoSql(IEnumerable<TEntity> list, SqlType sqlType)        {            return DoSql(list, sqlType, null);        }        /// <summary>        /// 执行SQL,根据SQL操作的类型        /// </summary>        /// <typeparam name="TEntity"></typeparam>        /// <param name="list"></param>        /// <param name="sqlType"></param>        /// <returns></returns>        private string DoSql(IEnumerable<TEntity> list, SqlType sqlType, params string[] fieldParams)        {            var sqlstr = new StringBuilder();            switch (sqlType)            {                case SqlType.Insert:                    list.ToList().ForEach(i =>                    {                        Tuple<string, object[]> sql = CreateInsertSql(i);                        sqlstr.AppendFormat(sql.Item1, sql.Item2);                    });                    break;                case SqlType.Update:                    list.ToList().ForEach(i =>                    {                        Tuple<string, object[]> sql = CreateUpdateSql(i, fieldParams);                        sqlstr.AppendFormat(sql.Item1, sql.Item2);                    });                    break;                case SqlType.Delete:                    list.ToList().ForEach(i =>                    {                        Tuple<string, object[]> sql = CreateDeleteSql(i);                        sqlstr.AppendFormat(sql.Item1, sql.Item2);                    });                    break;                default:                    throw new ArgumentException("请输入正确的参数");            }            return sqlstr.ToString();        }        /// <summary>        /// SQL操作类型        /// </summary>        protected enum SqlType        {            Insert,            Update,            Delete,        }        #endregion    }
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以上六大部分就是我最新的EF架构的核心了,事实上,EF只是实现数据持久化的一种方式,在我的架构中还提到了XmlRepository,RedisRepository,Linq2SqlRepository等等,对于仓储这块感兴趣的同学,可以与我一起去讨论!我很希望有一天,我的底层

架构有这样一个功能,那就是自动去选择我的数据库,如我的数据库有db1,db2.....dbN,它们之间的数据是同步的(集群),我能通过EF来实现我用哪台数据服务器,想想就很美,哈哈!

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EF架构~基于EF数据层的实现